# Regulation of Melanoma Cell Malignancy by Compartmentalized Chemokine Receptor Signaling

> **NIH NIH R21** · NEW YORK UNIVERSITY · 2022 · $412,686

## Abstract

Project Summary
Melanoma is the deadliest form of skin cancer with few treatment options to patients with advanced metastatic
disease. Melanoma cell proliferation, survival, invasion, and metastasis to lymph nodes correlates with
expression of the chemokine receptor CCR7. CCR7 is a member of the highly druggable G protein-coupled
receptors (GPCRs) superfamily and promotes cell migration and maturation of immune cells. Classically, upon
agonist stimulation, GPCRs at the cell membrane activate heterotrimeric G proteins, causing downstream
signaling throughout the cell. In order to terminate G protein signaling, cells have devised a specialized
desensitization mechanism that includes receptor phosphorylation by GPCR kinases and subsequent
recruitment of β-arrestins (βarrs) to the phosphorylated receptors. The GPCR–βarrs interaction both blocks the
G protein-binding site and promotes receptor endocytosis. However, we recently discovered that some GPCRs
interact with G proteins and βarrs simultaneously to form GPCR–G protein–βarr `megaplexes', which allows the
receptor to continue to stimulate G protein signaling while being internalized into endosomes by βarrs. Our
preliminary results suggest that CCR7 forms such megaplexes and continues to stimulate G protein signaling
after having been internalized. The proposed project aims to explore the involvement of this endosomal CCR7
signaling in malignant progression of melanoma cells. To this end, we have developed an experimental approach
to separate pathophysiological functions initiated by plasma membrane CCR7 signaling from endosomal CCR7
signaling. This approach leverages two natural chemokine ligands, CCL19 and CCL21, which predominately
activate G proteins from endosomes or plasma membrane, respectively. Using these chemokines to stimulate
CCR7 in HEK293 cells, we demonstrate that signaling from different cellular compartments promote distinct
transcriptional changes. In particular, we observed upregulation of key genes involved in the cholesterol
biosynthesis in response to endosomal CCR7 signaling whereas plasma membrane CCR7 signaling enhanced
the expression of inhibitory SMADs and other genes related to the transforming growth factor-β (TGF-β) pathway.
In melanoma, these two pathways are reported to have opposite effects with cholesterol production accelerating
melanoma cell proliferation and inhibitory SMADs limiting growth. Therefore, we here propose to test the
hypothesis that endosomal CCR7 signaling in melanoma specifically drives pathogenic cell proliferation through
enhanced cholesterol biosynthesis. The results from this project will not only enhance our understanding of how
chemokine receptor expression promotes melanoma malignancy but might also provide a new strategy to
develop effective melanoma therapeutics by targeting chemokine receptors at endosomal compartments.

## Key facts

- **NIH application ID:** 10528741
- **Project number:** 1R21CA243052-01A1
- **Recipient organization:** NEW YORK UNIVERSITY
- **Principal Investigator:** Alex Rojas Bie Thomsen
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $412,686
- **Award type:** 1
- **Project period:** 2022-09-23 → 2024-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10528741

## Citation

> US National Institutes of Health, RePORTER application 10528741, Regulation of Melanoma Cell Malignancy by Compartmentalized Chemokine Receptor Signaling (1R21CA243052-01A1). Retrieved via AI Analytics 2026-05-27 from https://api.ai-analytics.org/grant/nih/10528741. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*